Both the Nazis and the Stalinists used the term to denigrate anyone that wasn't sufficiently patriotic or nationalistic, that is, who considered themselves "citizens of the world" as opposed to proper Aryans or Marxists, respectively. The fact Miller used that particular term instinctively tells me he isn't just accusing the reporter of being a "man of the world" or a "sophisticated man-about-town" as we now use the term. He's revealing his pedigree and his philosophical antecedents. Your comparison to Goebbels is apt, but you could just have easily used Roy Cohn's image to make your point.

Roy Marcus Cohn (/koʊn/; February 20, 1927 – August 2, 1986) was an American attorney. During Senator Joseph McCarthy's investigations into Communist activity in the United States during the Second Red Scare, Cohn served as McCarthy's chief counsel and gained special prominence during the Army–McCarthy hearings.

He was also known for being a U.S. Department of Justice prosecutor at the espionage trial of Julius and Ethel Rosenberg and later for representing Donald Trump during his early business career.